But this is not altogether true, though it is true in a way. Among the gods, indeed, we may venture to say it is not true at all; but of that which is just among us part is natural, though all is subject to change. Though all is subject to change, nevertheless, I repeat, part is natural and part not.

Nor is it hard to distinguish, among things that may be other than they are, that which is natural from that which is not natural but dependent on law or convention, though both are alike variable. In other fields we can draw the same distinction; we say, for instance, that the right hand is naturally the stronger, though in any man the left may become equally strong.